1. Field of Invention
The current invention relates generally to apparatus, systems and methods for locating mobile units using wireless messaging. More particularly, the apparatus, systems and methods relate to locating mobile units with navigation and ranging. Specifically, the apparatus, systems and methods provide for locating mobile units using networking layers above the Organization for Standardization's (ISO) Open Systems Interconnection (OSI) model's Medium Access Controller (MAC) layer.
2. Description of Related Art
In the prior art, many systems need a “Denied GPS” capability, in that they must be able to determine their local time and position even if GPS signals are unavailable. Certain known systems provide such a capability. The terminals in such systems may tend to be very specialized, and hence very expensive. The prior art systems were expensive because they often required special hardware at the lower Physical (PHY) layer and the MAC layer that needed to calculate, often with hardware, their range, time and position. A need, therefore, exists for a way to more cost effectively determine range, time and position and to determine it in a way that can be leveraged by many different types of navigation links.